The present disclosure relates generally to communication networks, and, more particularly, to methods, systems, and computer program products for providing a common transport domain for use by multiple service domains by divorcing the distribution of loopback addresses for node reachability in the network from the signaling of the particular service.
Some Interior Gateway Protocols (IGPs), such as Open Shortest Path First (OSPF), allow an Autonomous System (AS) network, for example, to be partitioned into multiple areas to improve routing scalability within particular routing domains. Networks that use Multiprotocol Label Switching (MPLS) for routing, such as Virtual Private LAN Service (VPLS) networks, are required by the MPLS Label Distribution Protocol (LDP) to distribute loopback addresses for all Label Edge Routers (LERs) across all of the OSPF areas. Unfortunately, the deployment of a service that requires a large footprint of Provider Edges (PEs) may require many non-zero AS areas to be defined. For example, implementation of a VPLS service may create many non-zero areas that are aligned with the specific metro area that a set of PEs are deployed in. As a result, the number of routers and Label Switch Paths (LSPs) may grow rapidly, possibly to the point that it may be difficult to scale the OSPF core backbone area zero to support all of the non-zero areas.